Establishing the volatile organic compound profile and detection capabilities of human remain detection dogs to human bones

Abstract

The detection of skeletal remains using human remain detection dogs (HRD) is often reported anecdotally by handlers to be a challenge. Limited studies have been conducted to determine the volatile organic compounds (VOCs) emitted from bones, particularly when there is limited organic matter remaining. This study aimed to determine the VOCs emitted from dry, weathered bones and examine the detection performance of HRD dogs on these bones when used as training aids. The VOCs of four different bones (clavicle, rib, humerus, and vertebrae) from three cadavers were collected using sorbent tubes and analyzed using comprehensive two-dimensional gas chromatography‒time-of-flight mass spectrometry (GC × GC‒TOFMS). Subsequently, the responses of the HRD dogs to the bone samples were recorded over two separate two-day trials. A total of 296 VOCs were detected and classified into chemical classes, with aromatics and linear aliphatics being the most abundant classes. Several differences in the chemical class distribution were observed between the bone types, but the number and intensity of the VOCs were similar between the bone samples. During the HRD dog training, a higher false detection rate was observed on the first day of each trial; however, the detection rate improved to 100 % on the second day of each trial. Although the dogs are capable of detecting bones, they require exposure to and training with a diverse range of skeletal remains to enhance their efficiency. This is necessary due to the variations in the types and intensity of VOCs compared to earlier decomposition stages involving soft tissue.

Keywords

• Forensic taphonomy
• Decomposition chemistry
• Skeletal remains
• Canine detection
• Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS)